Knife gate valves are often used as isolation or shut-off valves. A knife gate valve is often intended to shut-off flow without regard to the direction of flow or the direction in which pressure is applied relative to the valve.
Most knife gate valves include a seat. The seat usually goes through a packing area or chamber at the top of the valve body. The point where the packing in the packing chamber, the seat and the gate intersect can create a leak path. The leak path is frequently overcome by significant compression of the packing The significant compression of the packing can lead to very high thrust loads during operation of the gate.
Accordingly, there is a need for a knife gate valve that requires less force to terminate leaks.